The present invention relates to rotors for caliper disc brakes and the like, and in particular to an improved method of forming a cross vented brake rotor.
Rotors are generally well known in the art, and are used extensively in vehicle braking systems, power transmission devices, clutches, and other similar machinery and mechanisms. Vehicle caliper disc braking systems slow the vehicle by inhibiting the rotation of the vehicle wheels. Rotors used in typical braking systems include a central hat section for attaching the rotor to a vehicle wheel and drive member for rotation therewith, and an outer friction portion having a pair of annular ring sections with opposed friction surfaces.
A caliper assembly secured to a non-rotating component of the vehicle, such as the vehicle frame. The caliper assembly includes a pair of brake pads disposed adjacent the rotor friction surfaces, and a moveable piston operatively connected to one or more of the brake pads. When the driver brakes the vehicle, hydraulic or pneumatic forces move the piston which clamps the pads against the friction surfaces of the rotating rotor. As the brake pads press against the moving rotor friction surfaces, frictional forces are created which oppose the rotation of the wheels and slow the vehicle. The friction converts the vehicle's kinetic energy into large quantities of heat, much of which is absorbed by the friction surfaces and conducted to the rest of the rotor and to other components to which the rotor is connected
Excess heat leads to premature brake wear and/or failure. Therefore a brake rotor should quickly transfer and dissipate the heat generated during braking. Vents have been formed in the friction surfaces of the rotor to circulate air around the annular peripheral section for cooling the brake. Cross vented rotors typically have vents extending in the axial direction through the friction surfaces.
Brake rotors are typically cast from a ferrous material such as cast grey iron, and then are machined in multiple operations to shape the hat section and friction surfaces. In general, solid cast iron or cast aluminum rotors are preferred from the standpoint of strength. Rotors having cross vented friction surfaces, are typically produced by initially casting a solid rotor which is then subjected to relatively extensive machining operations to form the vents. While this has proven to be an effective means of producing vented rotors, the additional machining operations increase the cost of manufacturing such rotors. It would therefore be advantageous to provide a method of forming a cross vented rotor which is less expensive than the conventional method, and which may not be significantly more expensive than the conventional method of forming a full cast, solid rotor.